The present invention relates to a production process for a fiber-filled thermoplastic resin composition having excellent mechanical characteristics.
It has so far been known to improve properties such as a mechanical strength by charging fibrous materials and various fillers into a thermoplastic resin. Disclosed in Japanese Patent Application Laid-Open No. 10837/1975 is a reinforced polyolefin resin composition prepared by adding maleic anhydride or itaconic acid and a specific inorganic metal compound such as magnesium oxide and magnesium hydroxide to polyolefin to react them and then mix glass fibers therewith.
However, the reinforcing effect thereof is not necessarily satisfactory.
An object of the present invention is to provide a production process for a fiber-filled thermoplastic resin composition which provides processed articles having high impact strength and which has a high fluidity.
The first production process of the present invention for a fiber-filled thermoplastic resin composition is as follows:
(1) A production process for a long fiber-filled thermoplastic resin composition, comprising:
using an apparatus having an extruder with at least two raw material feeding ports and at an end thereof (lowest downstream side), a resin-impregnating bath for impregnating bundles of continuous fibers with a molten resin liquid,
feeding a fixed amount of a resin mixture comprising a resin containing polyolefin, an unsaturated carboxylic acid and an organic peroxide; a resin containing polyolefin, an unsaturated carboxylic anhydride and an organic peroxide; or a resin containing polyolefin, an unsaturated carboxylic acid, an unsaturated carboxylic anhydride and an organic peroxide to a raw material feeding port (first feeding port) on an upstream side of the extruder,
feeding a fixed amount of at least one alkaline earth metal selected from the group consisting of substances, hydroxides and oxides of alkaline earth metals to a raw material feeding port (second feeding port) on a downstream side of the extruder, which is disposed in a position where the above mixture is sufficiently melt-kneaded.
allowing a molten resin mixture obtained by melt-kneading to flow into the impregnating bath described above,
passing a continuous fiber bundle through the molten resin mixture in this impregnating bath to impregnate the continuous fiber bundle with the above resin mixture,
drawing the above fiber bundle from a resin-impregnated fiber outlet having an adjustable aperture to thereby align the long fibers in the same direction and control the fiber content, and
then solidifying it.
(2) The production process for a long fiber-filled thermoplastic resin composition as described in the above item (1), wherein the resin mixture comprising 94 to 20% by weight of the resin containing polyolefin, 0.01 to 5.0% by weight of the unsaturated carboxylic acid or/and the unsaturated carboxylic anhydride and 0.01 to 0.5% by weight of the organic peroxide is fed to the first feeding port; 0.01 to 5.0% by weight of the alkaline earth metal is fed to the second feeding port; and the aperture of the resin-impregnated fiber outlet is adjusted so that the fiber content becomes 5 to 80% by weight (provided that % by weight is a value based on the resin composition to be produced).
The second production process of the present invention for a fiber-filled thermoplastic resin composition is as follows:
(3) A production process for a short fiber-filled thermoplastic resin composition, comprising:
feeding a fixed amount of a resin mixture comprising a resin containing polyolefin, an unsaturated carboxylic acid and an organic peroxide; a resin containing polyolefin, an unsaturated carboxylic anhydride and an organic peroxide; or a resin containing polyolefin, an unsaturated carboxylic acid, an unsaturated carboxylic anhydride and an organic peroxide to a raw material feeding port (first feeding port) on an upstream side of an extruder having at least three raw material feeding ports,
feeding a fixed amount of at least one alkaline earth metal selected from the group consisting of substances, hydroxides and oxides of alkaline earth metals to a raw material feeding port (second feeding port) to melt-knead them,
feeding a fixed amount of a fibrous material from a third feeding port to further melt-knead them, and
then cooling and pelletizing the mixture.
(4) The production process for a short fiber-filled thermoplastic resin composition as described in the above item (3), wherein the resin mixture comprising 94 to 20% by weight of the resin containing polyolefin, 0.01 to 5.0% by weight of the unsaturated carboxylic acid or/and the unsaturated carboxylic anhydride and 0.01 to 0.5% by weight of the organic peroxide is fed to the first feeding port; 0.01 to 5.0% by weight of the alkaline earth metal is fed to the second feeding port; and 5 to 80% by weight of the fibrous material is further fed from the third feeding port (provided that % by weight is a value based on the resin composition to be produced).